Debian Bug report logs - #314334
apt: APT doesn't work on filesystems without shared writable mmap(), like JFFS2.

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: "Matthew S. Wood" <matt@realmsys.com>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: apt: APT doesn't work on filesystems without shared writable mmap(), like JFFS2.

Date: Wed, 15 Jun 2005 13:14:13 -0600

Package: apt
Version: 0.5.28.6
Severity: important
Tags: patch

APT doesn't work on filesystems which don't support shared writable mmap.  This is significant for hand-held devices which use NAND flash as a data store.  These devices typically use a filesystem like JFFS2, which lacks shared writable mmap support.

The attached patch optionally implements [at compile time] support for mmap() emulation within APT.  In order for this support to properly function, a modification to the FileFd class was required.  This modification makes the FileFd class keep a cache of open files, such that if two contexts both hold the same file descriptor, the file descriptor isn't closed until both FileFd destructors are called.

The aforementioned patch corrects this issue.

-- Package-specific info:

-- /etc/apt/preferences --

Package: *
Pin: release a=experimental
Pin-Priority: 101

Package: libgcc1-powerpc-cross
Pin: release v=3.4.3-1
Pin-Priority: 1001

-- (/etc/apt/sources.list present, but not submitted) --


-- System Information:
Debian Release: 3.1
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (101, 'experimental')
Architecture: i386 (i686)
Kernel: Linux 2.6.11.11.msw3
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages apt depends on:
ii  libc6                       2.3.2.ds1-21 GNU C Library: Shared libraries an
ii  libgcc1                     1:3.4.3-12   GCC support library
ii  libstdc++5                  1:3.3.5-12   The GNU Standard C++ Library v3

-- no debconf information

--- PATCH HERE ---

diff -urp apt-0.6.25.orig/apt-pkg/contrib/fileutl.cc apt-0.6.25/apt-pkg/contrib/fileutl.cc
--- apt-0.6.25.orig/apt-pkg/contrib/fileutl.cc	2002-09-13 23:29:22.000000000 -0600
+++ apt-0.6.25/apt-pkg/contrib/fileutl.cc	2005-06-13 10:49:02.000000000 -0600
@@ -36,6 +36,9 @@
 
 using namespace std;
 
+
+map<int, int> FileFd::ref_count_map;
+
 // CopyFile - Buffered copy of a file					/*{{{*/
 // ---------------------------------------------------------------------
 /* The caller is expected to set things so that failure causes erasure */
@@ -415,6 +418,7 @@ bool FileFd::Open(string FileName,OpenMo
 
    if (iFd < 0)
       return _error->Errno("open",_("Could not open file %s"),FileName.c_str());
+   inc_ref(iFd);
    
    this->FileName = FileName;
    SetCloseExec(iFd,true);
@@ -573,13 +577,11 @@ unsigned long FileFd::Size()
 bool FileFd::Close()
 {
    bool Res = true;
-   if ((Flags & AutoClose) == AutoClose)
-      if (iFd >= 0 && close(iFd) != 0)
-	 Res &= _error->Errno("close",_("Problem closing the file"));
+
+   Res &= dec_ref(iFd);
    iFd = -1;
    
-   if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail &&
-       FileName.empty() == false)
+   if ((Flags & Fail) && (Flags & DelOnFail) && !FileName.empty())
       if (unlink(FileName.c_str()) != 0)
 	 Res &= _error->WarningE("unlnk",_("Problem unlinking the file"));
    return Res;
diff -urp apt-0.6.25.orig/apt-pkg/contrib/fileutl.h apt-0.6.25/apt-pkg/contrib/fileutl.h
--- apt-0.6.25.orig/apt-pkg/contrib/fileutl.h	2001-05-06 23:06:52.000000000 -0600
+++ apt-0.6.25/apt-pkg/contrib/fileutl.h	2005-06-13 11:43:35.000000000 -0600
@@ -1,4 +1,4 @@
-// -*- mode: cpp; mode: fold -*-
+// -*- mode: cpp; mode: fold; c-basic-offset: 3 -*-
 // Description								/*{{{*/
 // $Id: fileutl.h,v 1.26 2001/05/07 05:06:52 jgg Exp $
 /* ######################################################################
@@ -25,12 +25,51 @@
 #pragma interface "apt-pkg/fileutl.h"
 #endif 
 
+#include <apt-pkg/error.h>
+
+#include <apti18n.h>
+
 #include <string>
+#include <map>
+#include <cassert>
 
 using std::string;
+using std::map;
 
 class FileFd
 {
+   private:
+   /*
+    * Helpers to impelment reference counting on file descriptors.
+    * This is done to avoid closing a file descriptor which is shared
+    * by two different scopes.  If this is to be made thread-safe,
+    * a mutex must be in place. - MSW 06/10/2005
+    */
+   typedef int fd_t;
+   static map<fd_t, int> ref_count_map;
+   void inc_ref(int fd) {
+      if (fd >= 0) {
+	 if (ref_count_map.find(fd) == ref_count_map.end())
+	    ref_count_map[fd] = 1;
+	 else
+	    ref_count_map[fd] += 1;
+      }
+   }
+   bool dec_ref(int fd) {
+      int ret = true;
+      if (fd >= 0) {
+	 assert(ref_count_map.find(fd) != ref_count_map.end());
+	 ref_count_map[fd] -= 1;
+	 if (ref_count_map[fd] == 0 && Flags & AutoClose) {
+	    if (close(fd) < 0)
+	       ret = _error->Errno("close",
+				   _("Problem closing the file"));
+	    ref_count_map.erase(fd);
+	 }
+      }
+      return ret;
+   }
+
    protected:
    int iFd;
  
@@ -62,12 +101,13 @@ class FileFd
    
    // Simple manipulators
    inline int Fd() {return iFd;};
-   inline void Fd(int fd) {iFd = fd;};
+   inline void Fd(int fd) {dec_ref(iFd); iFd = fd; inc_ref(iFd);};
    inline bool IsOpen() {return iFd >= 0;};
    inline bool Failed() {return (Flags & Fail) == Fail;};
    inline void EraseOnFailure() {Flags |= DelOnFail;};
    inline void OpFail() {Flags |= Fail;};
    inline bool Eof() {return (Flags & HitEof) == HitEof;};
+   inline void SetAutoClose() {Flags |= AutoClose;};
    inline string &Name() {return FileName;};
    
    FileFd(string FileName,OpenMode Mode,unsigned long Perms = 0666) : iFd(-1), 
@@ -75,8 +115,8 @@ class FileFd
    {
       Open(FileName,Mode,Perms);
    };
-   FileFd(int Fd = -1) : iFd(Fd), Flags(AutoClose) {};
-   FileFd(int Fd,bool) : iFd(Fd), Flags(0) {};
+   FileFd(int Fd = -1) : iFd(Fd), Flags(AutoClose) { inc_ref(Fd); };
+   FileFd(int Fd,bool) : iFd(Fd), Flags(0) { inc_ref(Fd); };
    virtual ~FileFd();
 };
 
diff -urp apt-0.6.25.orig/apt-pkg/contrib/mmap.cc apt-0.6.25/apt-pkg/contrib/mmap.cc
--- apt-0.6.25.orig/apt-pkg/contrib/mmap.cc	2001-05-26 23:19:30.000000000 -0600
+++ apt-0.6.25/apt-pkg/contrib/mmap.cc	2005-06-14 16:53:11.000000000 -0600
@@ -1,4 +1,4 @@
-// -*- mode: cpp; mode: fold -*-
+// -*- mode: cpp; mode: fold; c-basic-offset: 3 -*-
 // Description								/*{{{*/
 // $Id: mmap.cc,v 1.22 2001/05/27 05:19:30 jgg Exp $
 /* ######################################################################
@@ -33,9 +33,117 @@
 
 #include <sys/mman.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
-   									/*}}}*/
+#include <errno.h>
+
+#ifdef USE_NO_MMAP_FALLBACK
+map<struct key, struct mem_cache, stat_eq > MMap::cached_mem;
+
+
+/*
+ * buf_read and buf_write initially called one common function to do the
+ * real loop, because the code is so similar.  This was abandoned, however,
+ * due to C++ type strictness and the slightly different function signatures
+ * of read and write.
+ */
+static inline bool buf_write(int fd, const void *buf, size_t count)
+{
+   size_t bytes_rem = count;
+   ssize_t ret;
+   while (bytes_rem > 0) {
+      int offset = count - bytes_rem;
+      ret = write(fd, ((const char *) buf) + offset, bytes_rem);
+      if (ret < 0)
+	 return _error->Errno("write",  _("Short write returned on fd %d.\n"), fd);
+      bytes_rem -= ret;
+   }
+   return true;
+}
+
+static inline bool buf_read(int fd, void *buf, size_t count)
+{
+   size_t bytes_rem = count;
+   ssize_t ret;
+   while (bytes_rem > 0) {
+      int offset = count - bytes_rem;
+      ret = read(fd, ((char *) buf) + offset, bytes_rem);
+      if (ret < 0)
+	 return _error->Errno("read",
+			      _("Short read returned on fd %d.\n"), fd);
+      bytes_rem -= ret;
+   }
+   return true;
+}
+
+bool MMap::fill_buffer(int fd, void **buf, unsigned long size)
+{
+   // First, see if the file has already been 'mapped'
+   struct mem_cache cache;
+   struct stat st_buf;
+   if (fstat(fd, &st_buf) < 0)
+      return _error->Errno("stat", _("Couldn't get file information."));
+
+   my_key.inode = st_buf.st_ino;
+   my_key.device = st_buf.st_dev;
+
+   /* We already have a cache of this file. */
+   if (cached_mem.find(my_key) != cached_mem.end()) {
+      cache = cached_mem[my_key];
+      if (cache.len < size)
+	 return _error->Errno("virtual_mmap",
+			      _("Virtual mmap can't grow shared memory"));
+      (*buf) = cache.ptr;
+      cache.ref_count++;
+      cached_mem[my_key] = cache;
+      return true;
+   }
+
+   /* There is no cache of this file */
+   (*buf) = malloc(size);
+   if (!(*buf))
+      return _error->Errno("malloc", _("Couldn't allocate %lu bytes memory"),
+			   size);
+   /*
+    * If the file is newly created, seek to the size we're requesting, 
+    * then write a byte to make it a sparse file.
+    */
+   if (st_buf.st_size < (long) size) {
+      if (lseek(fd, SEEK_SET, size) < 0) {
+	 free(*buf);
+	 return _error->Errno("lseek", _("couldn't create sparse file."));
+      }
+
+      char eof = 0;
+      if (!buf_write(fd, &eof, 1)) {
+	 free(*buf);
+	 return false;
+      }
+   } else {
+      lseek(fd, SEEK_SET, 0);
+      if (!buf_read(fd, *buf, size)) {
+	 free(*buf);
+	 return false;
+      }
+   }
+
+   cache.ptr = (*buf);
+   cache.len = size;
+   cache.ref_count = 1;
+   cached_mem[my_key] = cache;
+   return true;
+}
+
+# define PRINT_MMAP_WARNING()
+#else
+# define PRINT_MMAP_WARNING() \
+   if (errno == EINVAL) \
+      fprintf(stderr, "W: It is possible, though not likely, that your " \
+           "filesystem does not support shared writable mmap.  If this is " \
+           "truely the case, recompile apt with --enable-mmap-fallback.\n")
+#endif /* USE_NO_MMAP_FALLBACK */
+
 
 // MMap::MMap - Constructor						/*{{{*/
 // ---------------------------------------------------------------------
@@ -43,6 +151,9 @@
 MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
                      Base(0)
 {
+#ifdef USE_NO_MMAP_FALLBACK
+   baseMalloced = false;
+#endif
    if ((Flags & NoImmMap) != NoImmMap)
       Map(F);
 }
@@ -53,6 +164,9 @@ MMap::MMap(FileFd &F,unsigned long Flags
 MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
                      Base(0)
 {
+#ifdef USE_NO_MMAP_FALLBACK
+   baseMalloced = false;
+#endif
 }
 									/*}}}*/
 // MMap::~MMap - Destructor						/*{{{*/
@@ -80,12 +194,28 @@ bool MMap::Map(FileFd &Fd)
    
    if (iSize == 0)
       return _error->Error(_("Can't mmap an empty file"));
-   
-   // Map it.
-   Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
-   if (Base == (void *)-1)
-      return _error->Errno("mmap",_("Couldn't make mmap of %lu bytes"),iSize);
 
+#ifdef USE_NO_MMAP_FALLBACK
+   if (!(Map & MAP_SHARED)) {
+#endif
+      // Map it.
+      Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
+      if (Base == (void *)-1) {
+	 PRINT_MMAP_WARNING();
+	 return _error->Errno("mmap", _("Couldn't make mmap of %lu bytes"),
+			      iSize);
+      }
+#ifdef USE_NO_MMAP_FALLBACK
+   } else {
+      // Save off the passed file descriptor in case the caller closes it.
+      savedFd.Fd(Fd.Fd());
+      savedFd.SetAutoClose();
+
+      if (fill_buffer(savedFd.Fd(), &Base, iSize) < 0)
+	 return false;
+      baseMalloced = true;
+   }
+#endif
    return true;
 }
 									/*}}}*/
@@ -96,12 +226,29 @@ bool MMap::Close(bool DoSync)
 {
    if ((Flags & UnMapped) == UnMapped || Base == 0 || iSize == 0)
       return true;
-   
+
    if (DoSync == true)
       Sync();
-   
-   if (munmap((char *)Base,iSize) != 0)
-      _error->Warning("Unable to munmap");
+
+#ifdef USE_NO_MMAP_FALLBACK
+   if (baseMalloced) {
+      /*
+       * We always Sync in the case of malloc()'d memory because a
+       * free() won't sync to disk the way an munmap will.
+       */
+      if (!DoSync)
+	 Sync();
+
+      cached_mem[my_key].ref_count--;
+      if (!cached_mem[my_key].ref_count) {
+	 cached_mem.erase(my_key);
+	 free(Base);
+	 baseMalloced = false;
+      }
+   } else
+#endif
+      if (munmap((char *)Base,iSize) != 0)
+	 _error->Warning("Unable to munmap");
    
    iSize = 0;
    Base = 0;
@@ -116,12 +263,21 @@ bool MMap::Sync()
 {   
    if ((Flags & UnMapped) == UnMapped)
       return true;
-   
+
+#ifdef USE_NO_MMAP_FALLBACK
+   if (baseMalloced) {
+      if (Flags & ReadOnly)
+	 return true;
+
+      lseek(savedFd.Fd(), 0, SEEK_SET);
+      return buf_write(savedFd.Fd(), Base, iSize);
+   }
+#endif
 #ifdef _POSIX_SYNCHRONIZED_IO   
-   if ((Flags & ReadOnly) != ReadOnly)
-      if (msync((char *)Base,iSize,MS_SYNC) != 0)
-	 return _error->Errno("msync","Unable to write mmap");
-#endif   
+      if ((Flags & ReadOnly) != ReadOnly)
+	 if (msync((char *)Base,iSize,MS_SYNC) != 0)
+	    return _error->Errno("msync","Unable to write mmap");
+#endif
    return true;
 }
 									/*}}}*/
@@ -133,12 +289,22 @@ bool MMap::Sync(unsigned long Start,unsi
    if ((Flags & UnMapped) == UnMapped)
       return true;
    
+#ifdef USE_NO_MMAP_FALLBACK
+   if (baseMalloced) {
+      if (Flags & ReadOnly)
+	 return true;
+      unsigned long sz = Stop - Start;
+      lseek(savedFd.Fd(), Start, SEEK_SET);
+      return buf_write(savedFd.Fd(), ((char *) Base) + Start, sz);
+   }
+#endif
 #ifdef _POSIX_SYNCHRONIZED_IO
-   unsigned long PSize = sysconf(_SC_PAGESIZE);
-   if ((Flags & ReadOnly) != ReadOnly)
-      if (msync((char *)Base+(int)(Start/PSize)*PSize,Stop - Start,MS_SYNC) != 0)
-	 return _error->Errno("msync","Unable to write mmap");
-#endif   
+      if ((Flags & ReadOnly) != ReadOnly) {
+	 unsigned long PSize = sysconf(_SC_PAGESIZE);
+	 if (msync((char *)Base+(int)(Start/PSize)*PSize,Stop - Start,MS_SYNC) != 0)
+	    return _error->Errno("msync","Unable to write mmap");
+      }
+#endif  
    return true;
 }
 									/*}}}*/
diff -urp apt-0.6.25.orig/apt-pkg/contrib/mmap.h apt-0.6.25/apt-pkg/contrib/mmap.h
--- apt-0.6.25.orig/apt-pkg/contrib/mmap.h	2001-05-13 23:16:43.000000000 -0600
+++ apt-0.6.25/apt-pkg/contrib/mmap.h	2005-06-14 16:49:21.000000000 -0600
@@ -32,6 +32,39 @@
 #include <string>
 #include <apt-pkg/fileutl.h>
 
+#include <config.h>
+
+#ifdef USE_NO_MMAP_FALLBACK
+# include <map>
+# include <unistd.h>
+# include <sys/types.h>
+# include <sys/stat.h>
+
+# include <iostream>
+
+struct key {
+   ino_t inode;
+   dev_t device;
+};
+
+struct mem_cache {
+   void *ptr;
+   size_t len;
+   short ref_count;
+};
+
+
+struct stat_eq {
+   bool operator()(struct key k1, struct key k2) const {
+      if (k1.inode == k2.inode)
+	 return (k1.device < k2.device);
+      return (k1.inode < k2.inode);
+   }
+};
+
+using std::map;
+#endif
+
 using std::string;
 
 /* This should be a 32 bit type, larger tyes use too much ram and smaller
@@ -41,6 +74,17 @@ typedef unsigned int map_ptrloc;
 
 class MMap
 {
+#ifdef USE_NO_MMAP_FALLBACK
+   private:
+
+   static map<struct key, struct mem_cache, stat_eq > cached_mem;
+
+   bool baseMalloced;
+   FileFd savedFd;
+   struct key my_key;
+   bool fill_buffer(int fd, void **buf, unsigned long size);
+#endif
+
    protected:
    
    unsigned long Flags;
diff -urp apt-0.6.25.orig/apt-pkg/pkgcachegen.cc apt-0.6.25/apt-pkg/pkgcachegen.cc
--- apt-0.6.25.orig/buildlib/config.h.in	2002-11-22 00:15:23.000000000 -0700
+++ apt-0.6.25/buildlib/config.h.in	2005-06-14 17:05:20.000000000 -0600
@@ -43,3 +43,6 @@
 
 /* The package name string */
 #undef PACKAGE
+
+/* Define if mmap() emulation is needed. */
+#undef USE_NO_MMAP_FALLBACK
diff -urp apt-0.6.25.orig/configure.in apt-0.6.25/configure.in
--- apt-0.6.25.orig/configure.in	2004-06-09 06:30:22.000000000 -0600
+++ apt-0.6.25/configure.in	2005-06-14 17:00:49.000000000 -0600
@@ -18,7 +18,7 @@ AC_CONFIG_AUX_DIR(buildlib)
 AC_CONFIG_HEADER(include/config.h:buildlib/config.h.in include/apti18n.h:buildlib/apti18n.h.in)
 
 dnl -- SET THIS TO THE RELEASE VERSION --
-AC_DEFINE_UNQUOTED(VERSION,"0.6.25")
+AC_DEFINE_UNQUOTED(VERSION,"0.6.25-realm1")
 PACKAGE="apt"
 AC_DEFINE_UNQUOTED(PACKAGE,"$PACKAGE")
 AC_SUBST(PACKAGE)
@@ -189,6 +189,11 @@ rc_GLIBC_VER
 rc_LIBSTDCPP_VER
 ah_GCC3DEP
 
+AC_ARG_ENABLE(mmap-fallback,
+    [  --enable-mmap-fallback  Support emulation of mmap() ],
+    AC_DEFINE(USE_NO_MMAP_FALLBACK, 1,
+    ["Define if mmap() emulation is needed"]))
+
 dnl It used to be that the user could select translations and that could get
 dnl passed to the makefiles, but now that can only work if you use special
 dnl gettext approved makefiles, so this feature is unsupported by this.
diff -urp apt-0.6.25.orig/debian/changelog apt-0.6.25/debian/changelog
--- apt-0.6.25.orig/debian/changelog	2004-06-09 06:33:17.000000000 -0600
+++ apt-0.6.25/debian/changelog	2005-06-14 16:54:13.000000000 -0600
@@ -1,4 +1,11 @@
+apt (0.6.25-realm1) experimental; urgency=low
+
+  * Add mmap() emulation to apt for platforms which don't support
+    shared writable mmap.
+
+ -- Matthew S. Wood <matt@realmsys.com>  Tue, 14 Jun 2005 16:53:42 -0600
+
 apt (0.6.25) experimental; urgency=low
 
   * Fix handling of two-part sources for sources.list deb-src entries in

Message #10 received at 314334@bugs.debian.org (full text, mbox, reply):

From: Matt Zimmerman <mdz@debian.org>

To: "Matthew S. Wood" <matt@realmsys.com>, 314334@bugs.debian.org

Subject: Re: Bug#314334: apt: APT doesn't work on filesystems without shared writable mmap(), like JFFS2.

Date: Fri, 24 Jun 2005 15:23:10 -0700

severity 314334 wishlist
thanks

On Wed, Jun 15, 2005 at 01:14:13PM -0600, Matthew S. Wood wrote:
> Package: apt
> Version: 0.5.28.6
> Severity: important
> Tags: patch
> 
> APT doesn't work on filesystems which don't support shared writable mmap.
> This is significant for hand-held devices which use NAND flash as a data
> store.  These devices typically use a filesystem like JFFS2, which lacks
> shared writable mmap support.
> 
> The attached patch optionally implements [at compile time] support for
> mmap() emulation within APT.  In order for this support to properly
> function, a modification to the FileFd class was required.  This
> modification makes the FileFd class keep a cache of open files, such that
> if two contexts both hold the same file descriptor, the file descriptor
> isn't closed until both FileFd destructors are called.

Thanks for the patch. 

I am hesitant to complicate the code in this way in order to implement such
a workaround, though (especially with preprocessor macros).  I expect it
would be more gracefully implemented as a derived class.  What do you think?

-- 
 - mdz

Message #15 received at 314334@bugs.debian.org (full text, mbox, reply):

From: "James Harper" <james.harper@bendigoit.com.au>

To: <314334@bugs.debian.org>

Subject: This bug causes apt to break on OCFS2 too

Date: Tue, 25 Apr 2006 21:40:05 +1000

I'm just testing OCFS2 as a root filesystem, and apt breaks because
OCFS2 (and probably GFS) don't support shared writable mmap's. For OCFS2
at least, this support is on the todo list but not really near the top.

Any chance of an updated patch or, even better, something that detects
at runtime what the underlying filesystem supports and adjusts
accordingly?

Thanks

James

Message #22 received at 314334@bugs.debian.org (full text, mbox, reply):

From: Paul Sladen <debian@paul.sladen.org>

To: 314334@bugs.debian.org

Subject: apt-get on jffs2 / disabling cacheing completely

Date: Wed, 28 Nov 2007 12:50:19 +0000 (GMT)

Hit this "apt relying on shared writeable" issue today with a jffs2 issue.

N800/Maemo seem to have got around this by (I think using an older version
of apt?); it's all a bit messy and could really do with handling
transparently within apt.

First messages I found on this were from 2001, over at handhelds.org.  
Another option may just be to skipping the cacheing completely---it's
probably a bit unnecessary on flash devices with (relatively low) seek
times.

	-Paul
-- 
Why do one side of a triangle when you can do all three.  Helsinki, FI.

Message #27 received at 314334@bugs.debian.org (full text, mbox, reply):

From: "Lord of, St. Luke Valor" <lord.of.valor@gmail.com>

To: "Paul Sladen" <debian@paul.sladen.org>, 314334@bugs.debian.org

Subject: Re: Bug#314334: apt-get on jffs2 / disabling cacheing completely

Date: Wed, 28 Nov 2007 12:10:14 -0500

[Message part 1 (text/plain, inline)]

Dear M Sladen:

Is it possible to respond with a more specific description of the jfs2/apt
conflict? Any response is beneficial.

Due to the distributed nature of Bug Responses, someone may already be
developing a patch. Thank you for your contribution.

Luke

On 11/28/07, Paul Sladen <debian@paul.sladen.org> wrote:
>
> Hit this "apt relying on shared writeable" issue today with a jffs2 issue.
>
> N800/Maemo seem to have got around this by (I think using an older version
> of apt?); it's all a bit messy and could really do with handling
> transparently within apt.
>
> First messages I found on this were from 2001, over at handhelds.org.
> Another option may just be to skipping the cacheing completely---it's
> probably a bit unnecessary on flash devices with (relatively low) seek
> times.
>
>        -Paul
> --
> Why do one side of a triangle when you can do all three.  Helsinki, FI.
>
>
>
>
> --
> To UNSUBSCRIBE, email to deity-REQUEST@lists.debian.org
> with a subject of "unsubscribe". Trouble? Contact
> listmaster@lists.debian.org
>
>

[Message part 2 (text/html, inline)]

Message #32 received at 314334@bugs.debian.org (full text, mbox, reply):

From: Daniel Burrows <dburrows@debian.org>

To: "Lord of, St. Luke Valor" <lord.of.valor@gmail.com>, 314334@bugs.debian.org

Subject: Re: Bug#314334: apt-get on jffs2 / disabling cacheing completely

Date: Wed, 28 Nov 2007 21:26:44 -0800

On Wed, Nov 28, 2007 at 12:10:14PM -0500, "Lord of, St. Luke Valor" <lord.of.valor@gmail.com> was heard to say:
> Is it possible to respond with a more specific description of the jfs2/apt
> conflict? Any response is beneficial.

  The conflict is described in the bug log, along with some commentary
on possible solutions.  Basically, some filesystem drivers that are used
for embedded devices don't support shared writable mmaps, but apt requires
them.

  Daniel

Message #37 received at 314334@bugs.debian.org (full text, mbox, reply):

From: Petr Cervenka <Petr.Cervenka@interzonegames.com>

To: "'314334@bugs.debian.org'" <314334@bugs.debian.org>

Subject: Is this fixed in some package?

Date: Wed, 4 Jun 2008 09:30:24 +0800

[Message part 1 (text/plain, inline)]

Hi i have same problem with OCFS2, in chroot environment I can not do any work with apt, is there some option that allowed me to switch of mmap?
Is there any solution for this in debian etch?

Thanks

Petr Cervenka
IZ Linux System Administrator

[Message part 2 (text/html, inline)]

Message #42 received at 314334@bugs.debian.org (full text, mbox, reply):

From: Andres Salomon <dilinger@queued.net>

To: 314334@bugs.debian.org

Subject: Re: apt: APT doesn't work on filesystems without shared writeable mmap(), like JFFS2

Date: Wed, 20 Aug 2008 20:42:20 -0400

Hi,

Here's a workaround; keep the package caches on tmpfs.

dilinger@fred:~$ grep cache /etc/fstab 
tmpfs	/var/cache/apt/cache	tmpfs defaults	  0 0
dilinger@fred:~$ cat /etc/apt/apt.conf
Dir {
  Cache "var/cache/apt/" {
    srcpkgcache "cache/srcpkgcache.bin";
    pkgcache "cache/pkgcache.bin";
  };
};


tmpfs is capable of shared writeable mmap, so with this apt is usable
on jffs2.

Message #47 received at 314334@bugs.debian.org (full text, mbox, reply):

From: Loïc Minier <lool@dooz.org>

To: 314334@bugs.debian.org

Subject: Different patch from Maemo

Date: Fri, 26 Feb 2010 22:23:13 +0100

        Hi

 I was pointed at this patch by an Ubuntu user:
 http://www.mail-archive.com/maemo-commits@maemo.org/msg00201.html
 http://gitorious.org/mamona/openembedded/commit/4d4933fd97b85a52e48a5fa1a97bd34532864e32

 apparently developed for Maemo (I guess before switching to ubifs) and
 then picked up for mamona.

   Cheers
-- 
Loïc Minier

Message #52 received at 314334@bugs.debian.org (full text, mbox, reply):

From: David Kalnischkies <kalnischkies+debian@gmail.com>

To: Loïc Minier <lool@dooz.org>, 314334 <314334@bugs.debian.org>

Subject: Re: Bug#314334: Different patch from Maemo

Date: Sat, 27 Feb 2010 02:01:42 +0100

[Message part 1 (text/plain, inline)]

Hi Loïc Minier!

2010/2/26 Loïc Minier <lool@dooz.org>:
>  I was pointed at this patch by an Ubuntu user:
>  http://www.mail-archive.com/maemo-commits@maemo.org/msg00201.html
>  http://gitorious.org/mamona/openembedded/commit/4d4933fd97b85a52e48a5fa1a97bd34532864e32
Thanks for the pointers, unfortunately the patches never reached
"upstream" before - very bad as it is already three years old…

I have no facility to test it but at least it was tested by maemo
and openembedded so it can't be that bad and even if it would
be bad it can't be more bad than a failing apt anyway. ;)

Attach is a refreshed patch which should apply fine on top of the
recent apt's in version 0.7.25 or 0.7.26~exp2 --
and it would be brilliant if someone could test it. :)


Thanks again and
Best regards / Mit freundlichen Grüßen,


David Kalnischkies

[fallback-for-filesystem-without-mmap.patch (application/octet-stream, attachment)]

Message #59 received at 314334-close@bugs.debian.org (full text, mbox, reply):

From: Michael Vogt <mvo@debian.org>

To: 314334-close@bugs.debian.org

Subject: Bug#314334: fixed in apt 0.7.26~exp3

Date: Sat, 03 Apr 2010 13:40:45 +0000

Source: apt
Source-Version: 0.7.26~exp3

We believe that the bug you reported is fixed in the latest version of
apt, which is due to be installed in the Debian FTP archive:

apt-doc_0.7.26~exp3_all.deb
  to main/a/apt/apt-doc_0.7.26~exp3_all.deb
apt-transport-https_0.7.26~exp3_i386.deb
  to main/a/apt/apt-transport-https_0.7.26~exp3_i386.deb
apt-utils_0.7.26~exp3_i386.deb
  to main/a/apt/apt-utils_0.7.26~exp3_i386.deb
apt_0.7.26~exp3.dsc
  to main/a/apt/apt_0.7.26~exp3.dsc
apt_0.7.26~exp3.tar.gz
  to main/a/apt/apt_0.7.26~exp3.tar.gz
apt_0.7.26~exp3_i386.deb
  to main/a/apt/apt_0.7.26~exp3_i386.deb
libapt-pkg-dev_0.7.26~exp3_i386.deb
  to main/a/apt/libapt-pkg-dev_0.7.26~exp3_i386.deb
libapt-pkg-doc_0.7.26~exp3_all.deb
  to main/a/apt/libapt-pkg-doc_0.7.26~exp3_all.deb



A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 314334@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Michael Vogt <mvo@debian.org> (supplier of updated apt package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Format: 1.8
Date: Thu, 01 Apr 2010 17:30:43 +0200
Source: apt
Binary: apt apt-doc libapt-pkg-dev libapt-pkg-doc apt-utils apt-transport-https
Architecture: source all i386
Version: 0.7.26~exp3
Distribution: experimental
Urgency: low
Maintainer: APT Development Team <deity@lists.debian.org>
Changed-By: Michael Vogt <mvo@debian.org>
Description: 
 apt        - Advanced front-end for dpkg
 apt-doc    - Documentation for APT
 apt-transport-https - APT https transport
 apt-utils  - APT utility programs
 libapt-pkg-dev - Development files for APT's libapt-pkg and libapt-inst
 libapt-pkg-doc - Documentation for APT development
Closes: 314334 316390 351056 352667 383257 486222 500560 512046 512318 536029 558103 567669 570962 571037 572259 572364 572615 573293 573592 573946 574558 574944 574962
Changes: 
 apt (0.7.26~exp3) experimental; urgency=low
 .
   [ Christian Perrier ]
   * German translation update. Closes: #571037
   * Spanish manpages translation update. Closes: #573293
   * Dutch translation update. Closes: #573946
   * Polish manpages translation update. Closes: #574558
   * Add "manpages-pl (<< 20060617-3~)" to avoid file conflicts with
     that package that was providing some manpages for APT utilities.
 .
   [ David Kalnischkies ]
   * [BREAK] merge MultiArch-ABI. We don't support MultiArch,
     but we support the usage of the new ABI so libapt users
     can start to prepare for MultiArch (Closes: #536029)
   * Ignore :qualifiers after package name in build dependencies
     in the library by default, but try to honour them in apt-get
     as we have some sort of MultiArch support ready (Closes: #558103)
   * add translation of the manpages to PT (portuguese)
     Thanks to Américo Monteiro!
   * Switch to dpkg-source 3.0 (native) format
   * apt-pkg/depcache.cc:
     - remove Auto-Installed information from extended_states
       together with the package itself (Closes: #572364)
   * cmdline/apt-mark:
     - don't crash if no arguments are given (Closes: #570962)
   * debian/control:
     - remove some years old and obsolete Replaces
     - add automake/conf build-depends/conflicts as recommend by
       the autotools-dev README (Closes: #572615)
   * apt-pkg/contrib/mmap.{h,cc}:
     - add char[] fallback for filesystems without shared writable
       mmap() like JFFS2. Thanks to Marius Vollmer for writing
       and to Loïc Minier for pointing to the patch! (Closes: #314334)
   * doc/apt_preferences.5.xml:
     - fix two typos and be more verbose in the novice warning.
       Thanks to Osamu Aoki for pointing it out! (Closes: #567669)
     - fix a=sid vs. n=sid typo, thanks Ansgar Burchardt!
     - origin can be used to match a hostname (Closes: #352667)
     - remove wrong pin-priority is optional remark (Closes: #574944)
   * apt-pkg/deb/dpkgpm.cc:
     - fix error message construction in OpenLog()
     - if available store the Commandline in the history
   * cmdline/apt-get.cc:
     - add a --only-upgrade flag to install command (Closes: #572259)
     - fix memory leaks in error conditions in DoSource()
     - try version match in FindSrc first exact than fuzzy (LP: #551178)
   * apt-pkg/contrib/cmndline.cc:
     - save Commandline in Commandline::AsString for logging
   * apt-pkg/deb/debversion.cc:
     - consider absent of debian revision equivalent to 0 (Closes: #573592)
   * doc/makefile, doc/*:
     - generate subdirectories for building the manpages in on the fly
       depending on the po files we have.
   * apt-pkg/pkgcachegen.cc:
     - merge versions correctly even if multiple different versions
       with the same version number are available.
       Thanks to Magnus Holmgren for the patch! (Closes: #351056)
   * ftparchive/writer.cc:
     - write LongDescriptions if they shouldn't be included in Packages
       file into i18n/Translation-en by default.
   * doc/po/de.po:
     - correct a few typos in the german manpage translation.
       Thanks to Chris Leick and Georg Koppen! (Closes: #574962)
   * apt-pkg/contrib/strutl.cc:
     - convert all toupper calls to tolower_ascii for a little speedup
 .
   [ Jean-Baptiste Lallement ]
   * apt-pkg/contrib/strutl.cc:
     - always escape '%' (LP: #130289) (Closes: #500560)
     - unescape '%' sequence only if followed by 2 hex digit
     - username/password are urlencoded in proxy string (RFC 3986)
 .
   [ Julian Andres Klode ]
   * cmdline/apt-cache.cc:
     - Change behavior of showsrc to match the one of show (Closes: #512046).
   * cmdline/apt-key:
     - Honor Apt::GPGV::TrustedKeyring (Closes: #316390)
   * cmdline/apt-mark:
     - Use the new python-apt API (and conflict with python-apt << 0.7.93.2).
   * apt-inst/contrib/arfile.h:
     - Add public ARArchive::Members() which returns the list of members.
   * apt-pkg/policy.cc:
     - Always return a candidate if there is at least one version pinned > 0
       (Closes: #512318)
   * ftparchive/apt-ftparchive.cc:
     - Read default configuration (Closes: #383257)
   * debian/rules:
     - Fix the libraries name to be e.g. libapt-pkg4.9 instead of
       libapt-pkg-4.9.
 .
   [ Michael Vogt ]
   * apt-pkg/deb/dpkgpm.cc:
     - fix backgrounding when dpkg runs (closes: #486222)
   * cmdline/apt-mark:
     - show error on incorrect aguments (LP: #517917), thanks to
       Torsten Spindler
   * cmdline/apt-get.cc:
     - if apt-get source foo=version or foo/distro can not be found,
       error out (LP: #502641)
   * apt-pkg/packagemanager.cc:
     - better debug output
   * doc/examples/configure-index:
     - add missing Debug::pkgPackageManager option
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